Typewriting machine



/m/enor.' X410-1%@ Afm/nef March 3, 1931. A. E. HOWELL v TYPEWRITING MACHINE Filed Nov. 24, 1928 W W m1 .0.. H CII M W Mi lkmmmwww C0) a." I

. for typewriting machines.

Patented Mar. 3, 1931 UNITED vSTATES PATENT oFFicE- ABTHUR E. HOWELL, OF BROOKLYN, NEW YORK, ASSIGNOR TO UNDERWOOD ELLIOTT FISHER COMPANY, `0l' NEW YORK, N. Y., A CORPORATION .OF DELAWARE TYPEWRITING MACHINE Application led November 24, 1928. Serial No. 821,535.

This invention relates to revoluble In this invention the sound vibrations caused by type-impacts are diminished and largely absorbed by continuous fiexible'tubes of small diameter, which run longitudinally near the surface of the platen. These tubes weaken, distribute and bleak' uppthe vibrations, so that noises caused by the latter are deadened. This invention ma es possible two lhighly desirable results, namely: noiseless operation and clear printing. Furthermore, the platen is expensive.

In the construction illustrated, the .hard outer Wearing shell is made as usual and common, of vulcanized rubber composition.

In order to help deaden the sound of the type-impact on the outer shell, it is mounted on an inner sleeve made of material which is softer and 4more resilient. In this -sleeve there are embedded before vulcanization, a series of flexible tubes of small diameter,

I which lie side by side and run longitudinally for nearly the full length of the platen. These tubes are preferably of tightly coiled aluminum wire, which isvery light and also absorbs vibrations readily, and also because of its flexibility reduces the noise. Due to the great length of wire in each tube, the vibrations absorbed will follow the coils over long distances until theyv are weakened and become inaudible.

The aforementioned inner sleeve 1s 'drawn over a hollow wooden core which serves as a support, and also has sound-deadening qualities. The center of said core 1s bored `out to make it lighter, and also to provide a dead-air space, which still further reduces noise. To further minimize the latter, the inner surface of the core is covered with heavy paper, which is attached with adhesive.

When the platen has been built up, the usual" end plates are attached for supporting it in the carriage.

simple, lasting, efficient and in- The above construction has been found highly efficacious in deadening sounds. Each of its cylindrical elements areof sound-absorbingmaterial. lFurthermore, by using several differing materials, each has a different structure, which does not transmit sound-waves with uniformity, for the reason that sound-waves are bent, broken and impeded. The sounds therefore aresuccessively decreased by each cylindrical element .being more highly sound-deadening. Iii

more rigidly supporting the hard outer shell, the tubes must ofy necessity receive a greater number of vibrations. These are readily absorbed, however, by the many feet of wire in the coils of the tubes, whereby the tubes set up an advantageous resistance, and coucurrently absorb the greater number of vibrations so set up.

In accomplishing the sound-deadening, as explained, the prime essential is "the tubes. In so long as they are incorporated near the surface of the platen, their immediately adjacent structure is not so important. For this reason an alternative construction is shown in addition to the one above described. Such alternate construction is illustrated by Figures 3 and 4 and has three elements iii one form of construction the tubes are vulcanized lnto a composition-sleeve, and 1n the other the tubes interlie layers ofv felt or other sound-deadening material, which, taken as a unit, may also be considered as a sleeve.

- space Each form of construction has an advantageous use, as becomes apparent. When a typewriter is used for manifolding a comparatively few copies, the force of the typeblows is comparatively light, in order to save the type. Under such conditions little compression has to be resisted by the coiled wire ltubes, and very little rigidityl is needed therein. For this reason a fine aluminum wire may be used for lightness, and because it is not adversely affected by the heat necessary to vulcanize the sleeve. l

When a great number of sheets has to be manifolded, the type-impact is harder, in

which case more resistance 1s required in the walls of the coiled wire tubes in order to suprt the outer shell against the type-blows.A

nder these conditions it is advisable in forming the tubes, to use steel or otherhard wire.

An advantage of having the flexible tubes contiguous is, that more tubes can be used, and the vibrations received by any one tube are not alone carried along its own coils, but

will also be transmitted to adjacent ones. The vibrations therefore will radiate from the oint of t pe-impact, and will be more quic ly absor d and weakened to avoidl noise. l

Another sound-deadening feature resultant from the use of tubes, is the dead-air space formed by, which is hermetically sealed at each end for this purpose. The confined air within said has sound-deadening properties. Where fine aluminum wire is used, the tubes will not re'adily become permanently distorted under compression, and will not lose their usefulne.

While the above description pertains particularly to tubes made of coiled wire, it is not wished to limit this invention entirely to the use thereof. This because experiment has shown, that tubes of other material and form will also deaden sound very appreciably, when used in the manner shown and described.

Other features and advantages will hereinafter appear. a

In the accompanying drawings,

Figure l-is an enlarged cross-sectional view of a revoluble platen, and shows the tubes embedded in vulcanized soft -rubber composition.

Figure 2 is a partial longitudinal sectional view of the platen shown in Figure 1.

Figure 3 is a cross-sectional view of a revoluble platen, and shows the tubes interlying layers of felt or other sound-deadening material.

Figure 4 is a partial longitudinal sectional view of the platen shown'in Figure 3.

Referring to the drawings, 10 is a cornparatively hard outer wearing sleeve or shell of vulcanized rubber composition, against as shown in Fi and within, each tube,

are slightly shorter than the sleeve and have thin end walls air within the cavities formed by the tubes, and provide cushioning and sound-deadening features.

14:. The latter confine the l Thev two sleeves 1() and 12 are tightly mounted on a wooden core 15, which is bored out to leave a space 16. The circumferential wall of said space is covered with paper 17. The latter can be held against the wall by adhesive, or` can be a tube which is forced into said space. Through the space 16 there will normally run a shaft 19, which, by means of end plates 18, sup orts the platen in a typewriter-carriage. aid end plates have a tight fit on said shaft, to seal said s ace 16, and minimize the escape of soun -waves therefrom. The end plates 18 also have set screws 19, and countersun': screws 20, which attach said plates to said wooden core.

In the modified form of construction shown by Figures-3 and 4, all the parts are the same res 1 and 2, with the exception 'of thi` inner sleeve 12. In lieu of the latter there can be used a different form of sleeve, having layers 21 and 22 of sounddeadening material, such as felt, which are concentric, and have the tubes 13 interlying y the same. This modified construction can be applied in two ways. In the one, a layer 21 is attached by'adhesive to the wooden core 15, after which, adhesive is applied to the outside surface of said layer. The tubes are then applied and will adhere to the surface. Adhesive is next applied over the tubes, which are then covered bv the layer 22. When the adhesive 'has dried, the outer shell 1s drawn over the whole, and the end plates are attached.

Another method of assembling'the modified form of platen is to build up the two layers and interlying tubes as a unit. This is accomplished through the use of a mandrel, around which a layer, the tubes and another layer are respectively applied, and which are unified by adhesive on adjacent surfaces. When the adhesive is dry, the built-up sleeve is removed from the mandrel, and can be slipped over the wooden core. Before placing, however, the corecanbe coated with a thin layer of adhesive, which, when dry, will hold the sleeve, in place. As in the first method, the outer shell is then drawn over the inner sleeve, and the end plates are attached.

. In using the modified form of construction, a space is left at each end of the tubes, which, as previously'mentioned, are slightly shorter than the sleeve. In order to confine the air v felt.

within the cavities of the tubes, and thereby maintain an air-cushion, said spaces are sealed with sound-deadening material 23. The latter can be a viscous material that will dry out and become resilient, or it may be a ring of sound-deadening material, such as In portable typewriters, where lightness and compactness are requisites, the platens have smaller diameters than those of the standard models. Also as theportable models are not ordinarily used for manifolding a large number of copy-sheets, it is ossible to use a platen having a relatively so worksurace. It is a feature of this invention that it is particularly fitted to successfully aid just such conditions, as the wire helices afford a firm support against the type-blows, but are yieldable under said blows. n

In using this invention for portable typewriters, it may be applied to the platen by the two methods aforementioned, or still another modification may be employed. In the latter the core, while being of smaller diameter, can also have a central space of relativelyA large diameter, which will appreciably lighten the core. In order to maintain the smaller finished diameter of the platen, the composition covering will be made thinner. This thmner covering can, in fact, be made 1n one thickness or sleeve, which has the tubes embedded therein. l

In using a thin sleeve, as described, the small mass of material in the walls will not effectively deaden all the sounds of type1mpacts. This condition is ameliorated to some extent by the use of the softer material 1n the sleeve, which, however, would ordinarily be inimical to clear type-impressions. The ilexible tubes featured in' this invention stitfen this softer material, and therefore insure the clearer impressions. At the same time the coils of the tubes, and the dead-air spaces therein absorb and deaden the sounds. Furthermore, through increasingthe dead-air space within the core, more sound-waves are absorbed, and noise is still further reduced. This invention therefore makes possible the use of a small light platen, which is still high- .ly effective in deadening sounds.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I

claim:

1. In a typewriter-platen, a wooden core which is hollow, end plates attached to said core for mounting the same on a shaft, paper attached to the inner surface of said core, a resilient sleeve on said core, small tubes extending longitudinally of the platen and forming a circu-lar row in said sleeve, and a relatively hard resilient outer sleeve Whlch tightly fits over the other sleeve.

Q. In a typewriter-platen, a wooden core p ing to the ends of said sleeve,

' an outer shell,

which is hollow, end plates attached to said core for mounting the same on a shaft, a sleeve on said core, said sleeve of vulcanized rubber composition, which is resilient and tightly embraces the core, tubes embeddedv extending longitudinally thereof, said tubes y being of coiled wire, the tubes not extending to the ends of said sleeve, and a relatively hard outer sleeve of vulcanized rubber composition which is tightly fitted over the other sleeve.

4. In a typewriter-platen, a wooden core which is hollow, end plates attached to said core for mounting the same on a shaft, paper attached to the inner surface of said core, a sleeve of resilient sound-deadening material which tightly encom l asses said core, contiguous tubes embedde in said sleeve and extending longitudinally thereof, said tubes having resilient walls, the tubes not extendand a relatively hard outer sleeve of vulcanized rubber composition which is tightly fitted over the other sleeve. 4

5. In .a typewriter-platen, a wooden core which is hollow, end plates attached to said core for mounting the same on a shaft, paper `attached to the inner surface of said core, a resilient sleeve on said core, another sleeve tightly superimposed thereon and forming an outer shell, the latter of relatively hard vulcanized rubber composition, and contiguous tubes embedded in the first-mentioned sleeve, saidv tubes having resilient walls and forming cavities which are sealed by the surrounding material, said sealed cavities functioning as air cushions to absorb shocks when said outer shell is struck. 4

6. In a typewriter-platen, a wooden core which lis hollow, end plates attached to said core for mounting the same on a shaft, a re silient sleeve on said core, another sleeve tightly superimposed thereon and forming the latter of relatively hard vulcanized rubber composition, and contiguous tubes embedded in the first-mentioned sleeve, said tubes having resilient Walls and forming cavities which are sealed by the surrounding material, said sealed cavities forming dead air spaces, to absorb vibrations and deaden noise when said outer shell is struck.

7. In a typewriter-platen, a Wooden core which is hollow, end plates attached to said core for mounting the same on a shaft, paper ing.

I, bination of end` plates,

" mounting the same on a attached to the inner surface of said core, a resilient sleeve on said core, another sleeve tightly superimposed thereon and forming an outer shell, the latter of relatively hard vul-` canized rubber com osition, and conti ous tubes embedded in t e first-mentioned s eeve, said tubes having resilient walls and formcavities which are sealed by the sur'- rounding material, said sealed cavities funetionng as compression-chambers wherein the elasticity of the air lcompressed will help to restore said walls to normal positions after the walls have been distorted by a blow.

8. In a typewriter-platen, a-wooden core which is hollow,.end` plates attachedto said core for mounting the same on 'a shaft, paper attached to the inner surface of ysaid core, contiguous tubes surrounding said core and extending lonigtudinally thereof, a relatively hard t' htly-fitting outer sleeve of vulcanized rub r composition, and adhesive resilient material which respectively fills the interstices between said core and said tubes and between said tubes and said outer sleeve', andalso seals the ends of said tubes.

9. In aplaten for a typewriting machine, the vcombination of an outer sleeve or shell, a

wooden core which is hollow, end plates at-l tached to said core for mounting the same on a platen-shaft, paper attached to thel inner surface of said core, a cylindrical inner sleeve which ti htly fits between said shell and said core, sai inner sleeve havin interior and exterior circumferential wa of resilient sound-deadening material and having interlying contiguous tubes running longitudinally and not quite to the ends thereof to leave annular spaces, and resilient sound-deaden ing material which fills said spaces.

10. In a typewriter-platen, a core which is hollow, end plates attached to said core for shaft, paper attached to the inner surface of said core, 'a resilient sleeve on said core, and contiguous tubes embedded in said sleeve and extending longitudinally thereof.

11. A typewriter-platen including Vthe coma wooden core which is hollow and to which the end plates are attached, paper attached to the inner surfacel of said core, a shaft which supports the end plates and to which the latter are fastened, a

` usual line-spacing mechanism attached to the shaft, a mass of resilient com osite material which closely encompasses sai core, and contiguous tubes embedded in said material and extendin longitudinally thereof, saidtubes of such iameters and so positioned radially from the shaft that each can be made to underlie a. line of printing through registration with the line-spacing mechanism when typing is done on the platen.

12. In a typewriter-platen, a wooden core which is hollow, end plates attached to said r core for mounting the same on a shaft, paper 'bedded in sai hollow,

mounting said core,

ywhich is hollow, en d core for mounting said core on a platen-s attached tothe inner surface of said core, a osite material which and 'tubes emsounds thereof.

13. In a typewriter-platen,'a'corewhich means attac a mass of rubber composition encompassing said core, tubes embedded in said mass to absorb vibrations and y reduce noise when the platen is struck, and a' vtube of fibrous material within said core to further deaden said noise.

14. In a typewriter-platen, a wooden core p ates attached to said a tube of fibrous material engaging the inner 'walls of said core, rubber composition encompassing said core, and conti ous tubes embedded 1n said rubber composition to absorb vibrations and platen is struck, said near the surface of the platen.

15. A laten including a series of closelywound exible helices of wire extending lengthwise of the platen and closely assembled to serve as a locally-flexible tubular platen-body, a layer of soft sounddeadening material in which said helices are embedded, an louter hard wear-resisting element provided upon said layer, and a supportin core.

16. In a typewriter-platen, a core wldr hollow, means upon said core for mounting the same, a soft resilient sleeve on said core, another sleeve tightly superimposed thereon and forming an outer shell, the latter of rela tively hard vulcanized rubber composition, and contiguous flexible resilient wire helices embedded in the first-mentioned sleeve.

17.' lIn a typewriter-platen, a core which is hollow, means attached to said core for mounting the same, contiguous tubes surrounding said core and extending longitudinally thereof, a relatively hard tightly-fitting outer sleeve lof vulcanized rubber composition, and adhesive soft, resilient material which -respectively fills the interstices b`etween said core and said tubes and between said tubes and said outer sleeve.

18. A typewriter-platen including the comed to"the".same, for v haft,

deaden sound whenthe contiguous tubes being ich is 4with the line-spacing mechanism when typing is done on the platen.

19. In a typewriter-platen, a core which is hollow, means attached to lsaid core for mounting the same, a mass of resilient com- 

